Coupled Electron- and Phase-Transfer Reactions at a Three-Phase Interface (original) (raw)
Related papers
Chemical Physics Letters, 2004
An effective computational scheme to construct the adiabatic potential energy surfaces (APES) along the reaction coordinates for an electron transfer reaction occurring by two steps at a metal electrode is considered in the framework of the Anderson-Newns model. Two Theorems have been proved which predict the existence of all possible solutions of the Anderson-Newns equations at arbitrary values of the key parameters and point out the region for each solution. Asymptotic formulas for solutions near multiple roots have been derived and combined in an effective way with numerical routines. The analysis of some important properties of the APES, which can be of interest for modelling the electrochemical electron transfer processes, is presented as well. The APES describing the reduction of Zn(II) and In(III) aqua-complexes at a mercury electrode have been built and discussed.
Electrochimica Acta, 2018
The mathematical modelling of heterogeneous charge transfer processes complicated by the reactivity of the redox species in solution is revisited, elaborating on powerful and accurate theoretical approaches and simplifications that can facilitate and speed up the mathematical resolution, the solution implementation, the design of experiments and the calculation and analysis of the electrochemical response. The physicochemical fundamentals and mathematical implications behind such approaches will be discussed for frequent and paradigmatic reaction mechanisms involving homogeneous chemical equilibria and (pseudo)first-order and second-order chemical kinetics. The cases considered will point out how the suitable preliminary examination of the boundary value problem offers profound insights into the electrochemical system that can assist the design of theoretical and experimental studies. This provides criteria for the assessment of complex simulations (for example, by comparison with exact analytical solutions for particular cases) and it can alert about meaningless results derived from blind use of approximations and/or 'brute force' approaches.
Monte Carlo simulations of heterogeneous electron transfer: New challenges
Russian Journal of Electrochemistry, 2017
We report results of MC simulations of electron transfer across a metal electrode/electrolyte solution interface. The model presumes the Landau-Zener theory and a random walk on a two-dimensional lattice formed by crossing parabolic reaction free energy surfaces along the solvent coordinate. Emphasis is put on investigating the activationless discharge regime; the bridge-assisted electron transfer is also partially addressed. We have calculated effective electronic transmission coefficient as a function of the electrode overpotential and temperature in a wide range of orbital overlap. The dependence of the transmission coefficient on the electronic density of states is analyzed as well.
Electron-transfer reactions across liquid|liquid interfaces
Journal of Electroanalytical Chemistry, 1997
We present a general expression for the rate of an electron-transfer reaction across liquidlliquid interfaces. Since the variation of the inner potential in the boundary region is small, a change in the potential drop across the interface has little effect on the free energy of the reaction, but affects mainly the concentrations of the reactants. This argument is supported by explicit model calculations. © 1997 Elsevier Science S.A.
Influence of interionic separation in electron transfer reactions
Journal of Molecular Structure: THEOCHEM, 1999
A theoretical study is presented on the influence of the interionic separation between the reacting metal cations on the kinetics of electron transfer reactions. The results of some simulations are presented to characterize the dependence of the activation free energy of the electron transfer process relatively to the interionic separation as well as the potential of mean force between the two cations considered in this study, Cu ϩ and Cu 2ϩ , in aqueous medium. The use of truncation of coulombic interactions is compared with the use of Ewald sums in the treatment of long range interactions. The truncation of coulombic interactions in the simulations is observed to have a strong influence in the final results.
A unified model for electrochemical electron and ion transfer reactions
Chemical Physics Letters, 1995
Electron and ion transfer reactions on metal electrodes are considered in an extended Anderson model, in which the interactions of the reactant with the metal and with the solvent depend on the separation from the interface. The model allows the construction of effective potential energy surfaces. Explicit calculations are performed for the transfer of an iodide ion and for the electron transfer reaction of the Fe2+/Fe 3+ couple.
A model for electron-transfer reactions via adsorbed intermedaites
Journal of Electroanalytical Chemistry, 1980
A theory is presented for electron-transfer reactions between a strongly coupled metal electrode/adsorbate system and a simple redox system in solution. A model Hamiltonian is set up in which the adsorbate is described by the Anderson model; the current is then calculated within the transfer Hamiltonian formalism. An important factor in the equation for the current is the adsorbate density of states evaluated at the saddle point of the reaction hypersurface; an explicit expression for this quantity is derived. The relation of this work to experimental results and to other theories of electron-transfer reactions is discussed.
A simulation of an electrochemical adiabatic electron-transfer reaction
Chemical Physics Letters, 2000
Adiabatic electron exchange between an electroactive species and a metal electrode is investigated by molecular dynamics simulation. The system is assumed to be in contact with a thermal bath, which provides the activation energy required for an electron transfer. The method allows the explicit calculation of transmission factors. q 2000 Elsevier Science B.V. All rights reserved.